Suction gripper



July 9, 1940. G, SPIESS 2,207,492 v SUCTI ON GRIPPER Filed Feb. 18, 1958 Patented July 9, 194

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SUCTION GRIPPER Georg Spiess, Leipzig, Germany Application February 18, 1938, Serial No. 191,333

In Germany 2 Claims.

This invention relates to a suction gripper for sheet separating and feeding devices.

It is known to provide the body of the grippers serving for lifting a sheet or a portion thereof 5 from the pile and for gripping and holding the sheet during feeding with rubber rings to compensate small unevennesses of the pile and sheet surface when the gripper is applied and, particularly in case of rough-finished papers, toinsure good airtight contact between the paper and the suction pipe or suction opening of the gripper. Furthermore, suction members are known in which for the purpose of facilitating the lifting of the top sheet from the pile by a convex configuration of the application surface of the suction member and the arrangement of suction ducts therein communicating with a transverse duct air chambers and intermediate spaces are formed during sucking up of .the top sheet between the next sheet and the suction member, which communicate with the outer air. This is done to prevent the suction member from simultaneously picking up two or more sheets by avoiding the formation of a vacuum between the top sheet and the next following sheet.

yIt is further known to provide line suction openings in separated flat depressions of the suction surface of the suction members.

According to this invention the suction opening of the gripper body is covered with a rubber hood whose nat bottom is provided with one or more suction cups which communicate with the hollow space of the gripper body covered by the rubber bottom. In this way, highly elastic hug,- ging of the sheet by the suction surfaces or edges of the gripper and thereby good covering of the suction openings by the sheet are attained. Furthermore, owing tothe covering of the larger suction opening of the gripper body except for a few iine apertures fitted with suction cups, the suction effect is reduced and distributed in a manner which is particularly notedv when very light and porous papers are to be lifted. If suction members having a large opening and the corresponding great suction effect required for harder, denser, and stiffer papers are used for such lighter papers, it usually happens that several sheets are simultaneously lifted from the pile. This drawback is eliminated by the provision of the rubber cover which possesses ne suction cups and closes the suction opening of the suction gripper. The danger of picking up several sheets at a time is diminished already by the reduction and distribution of the suction effect. Moreover, as the rubber bottom is drawn March 8, 1937 into the hollow space of the gripper body, an additional sheet accidentally lifted will drop clown owing to the resistance of the paper.

By way of example, one form of the invention is illustrated in the accompanying drawing, in which Figure 1 is a. view of the underside of thev suction gripper and Fig. 2 a side view thereofv with the rubber cover shown in section.

The suction gripper l is placed in known manner on a suction rod 2 of a suction piping of the sheet separating and feeding device and correspondingly secured. The gripper I comprises in its upper portion a rod guide 3 corresponding to the cross section of the suction rod 2 and extending downwardly into a conical portion 4. Inside the gripper member l a suction chamber 5 of corresponding size is formed which is shut off downwardly by the inner surface 6 of the cover l for the gripper. The covery I is made of an elastic material and possesses on its lower bottom surface one, two or more suction cups 8 each of which has a suction opening 9 cornmunicating with the inside of the suction chamber 5. As Fig. 2 shows, the suction cups 8 are formed so that even if only lightly applied to the surface of the sheets Il) their outer edge Il will easily and without fail adapt itself to thev surface of the sheet, the grain of the paper, and other inequalities.

During picking up of the top sheet and withdrawal or rarefaction of the air in the suction chamber 5 the elastic cover l will tend to be drawn into the chamber 5, after the sheet is in contact with the lower suction plane of the cups 8, to such an extent that absolutely rm adherence of the surface of the picked up sheet is attained with maximum surety. For the drawing up and. adherence of the picked up sheet special forces are developed in so far as the sheet is not gripped at as many points as suction cups are provided. Another advantage is that the cover l drawn into the hollow space of the gripper body 5, owing to its elasticity for urging it into normal position, also has the effect of increasing the adhesion of the picked up sheet t0 the suction surface of the cups 8, and of preventing adherence of the lower sheet to the one being separated.

I claim:

1. In a suction nozzle for the lpurpose described, a rigid suction body having a chamber therein and having a mouth provided with a iiange forming a frusto-concal lip extending around and depending from the mouth, a exible rubber` hood extending across said mouth and 10 around and depending from the mouth, a flexible rubber hood extending across said mouth and provided with a peripheral frusta-conical ange engaging the exterior of the lip for removably holding the hood on the body, and at least one suction cup carried by the hood and communicating with said chamber, said suction cup being formed of rubber and integral with said hood.

GEORG SPIESS. 

